Resin particles, method for producing same, and uses of same

Abstract

Resin particles according to an embodiment of the present invention have a first glass transition temperature and a second glass transition temperature. The first glass transition temperature is -40°C to -20°C, and the second glass transition temperature is 100°C to 140°C. The resin particles have a dielectric loss tangent of 0.0050 or less at a measurement frequency of 10 GHz.

Description

Resin particles, method for producing the same, and use thereof

[0001] The present invention relates to resin particles, a method for producing the same, and use thereof.

[0002] In semiconductor members, in order to cope with high-frequency signals for next-generation high-speed communication and suppress transmission loss, reduction of dielectric constant, reduction of dielectric loss tangent, and thinning are required. Further, with thinning, suppression of warpage caused by heat history or the like is required. In order to reduce the dielectric constant, reduce the dielectric loss tangent, and suppress warpage, addition of resin particles having softness to semiconductor members has been studied.

[0003] For example, as conventional resin particles, organic fine particles having a core part with a glass transition temperature of -100°C to -30°C and a shell part with a glass transition temperature of 80°C to 120°C have been reported (Patent Document 1). However, since the shell part is formed by polymerization of an acrylic monomer, the value of the dielectric loss tangent is high. Further, the particle diameter is large, forming irregularities in the base resin, leading to deterioration of the dielectric loss tangent and adhesion.

[0004] Further, as conventional resin particles having a small particle diameter, fine particles having a core containing an acrylic resin and a glass transition temperature of 45°C or higher have been reported (Patent Document 2). However, since the fine particles described in Patent Document 2 have a high acrylic composition ratio, the value of the dielectric loss tangent is high. Further, since the glass transition temperature is high and it does not have softness, it is not suitable for the above uses.

[0005] Further, as conventional resin particles having a small particle diameter, there are particles produced by preparing polybutadiene latex by emulsion polymerization and then grafting by seed emulsion polymerization of methyl methacrylate and styrene (Patent Document 3). However, since the particles described in Patent Document 3 have a high acrylic composition ratio, the value of the dielectric loss tangent is high.

[0006] JP 2022 - 154756 A, JP 2018 - 184550 A, JP 2020 - 164578 A

[0007] This invention was made to solve the above-mentioned conventional problems, and its main objective is to provide resin particles having flexibility and excellent dielectric properties. It also aims to provide a method for producing such resin particles. Furthermore, it aims to provide applications for such resin particles.

[0008] [1] The resin particles according to the embodiment of the present invention have a first glass transition temperature and a second glass transition temperature, wherein the first glass transition temperature is -40.0°C to -20.0°C, the second glass transition temperature is 100.0°C to 140.0°C, and the dielectric loss tangent at a measurement frequency of 10 GHz is 0.0050 or less. [2] The resin particles described in [1] above may have an average particle diameter of 0.1 μm to 10.0 μm. [3] The resin particles described in [1] or [2] above contain a polymer P obtained by the reaction of a composition C containing a monomer component (M), wherein the monomer component (M) may contain a crosslinkable monomer (a) and a monofunctional monomer (b). [4] In the resin particles described in [3] above, the composition C may contain a reactive soft component that is reactive with the monomer component (M). [5] In the resin particles described in [4] above, the crosslinkable monomer (a) includes an aromatic crosslinkable monomer, and when the total of the monomer component (M) and the reactive soft component is 100 parts by weight, the aromatic crosslinkable monomer may be greater than 0 parts by weight and 30 parts by weight or less. [6] In the resin particles described in [4] or [5] above, the monofunctional monomer (b) includes an aromatic monofunctional monomer, and when the total of the monomer component (M) and the reactive soft component is 100 parts by weight, the aromatic monofunctional monomer may be 20 parts by weight or more. [7] In the resin particles described in any one of [4] to [6] above, when the total of the monomer component (M) and the reactive soft component is 100 parts by weight, the reactive soft component may be greater than 0 parts by weight and 30 parts by weight or less. [8] In the resin particles described in any one of [4] to [7] above, the reactive soft component may include polybutadiene. [9] In the resin particles described in any one of the above items [4] to [8], when the total amount of the monomer component (M) and the reactive soft component is 100 parts by weight, the (meth)acrylic compound may be less than 20 parts by weight.

[10] The resin particles described in any one of the above items [1] to [9] may have a dielectric loss tangent of 0.0030 or less at a measurement frequency of 10 GHz.

[11] The resin particles described in any one of the above items [1] to

[10] may be used in a resin composition for semiconductor materials.

[12] A resin composition for semiconductor materials according to an embodiment of the present invention contains the resin particles described in any one of the above items [1] to

[11] .

[13] A dispersion according to an embodiment of the present invention contains the resin particles described in any one of the above items [1] to

[10] .

[14] A method for producing resin particles according to an embodiment of the present invention comprises a two-step polymerization step consisting of a first polymerization step and a second polymerization step, wherein in the first polymerization step, a composition C1 containing a first monomer component (M1) and a reactive soft component is subjected to a suspension polymerization reaction, and in the second polymerization step, the product obtained in the first polymerization step and a second monomer component (M2) are subjected to an emulsion polymerization reaction, wherein the first monomer component (M1) includes a crosslinkable monomer (a1) and a monofunctional monomer (b1), and the second monomer component (M2) includes a crosslinkable monomer (a2) and a monofunctional monomer (b2).

[15] In the method for producing resin particles described in

[14] above, the crosslinkable monomer (a1) may include an aromatic crosslinkable monomer, and the monofunctional monomer (b1) may include an aromatic monofunctional monomer.

[16] In the method for producing resin particles described in

[14] or

[15] above, the reactive soft component may include polybutadiene.

[0009] According to embodiments of the present invention, it is possible to provide resin particles having flexibility and excellent dielectric properties. Furthermore, a method for producing such resin particles can be provided. In addition, applications for such resin particles can be provided.

[0010] The following describes embodiments of the present invention, but the present invention is not limited to these embodiments.

[0011] In this specification, the expression "(meth)acrylic" means "acrylic and / or methacrylic," the expression "(meth)acrylate" means "acrylate and / or methacrylate," and the expression "(meth)acrylonitrile" means "acrylonitrile and / or methacrylonitrile."

[0012] ≪≪Resin Particles≫≫ The resin particles according to the embodiment of the present invention have a first glass transition temperature and a second glass transition temperature, the first glass transition temperature being -40.0°C to -20.0°C and the second glass transition temperature being 100.0°C to 140.0°C. The resin particles according to the embodiment of the present invention, by having flexibility due to the first glass transition temperature, impart flexibility to a base resin such as a semiconductor component when added to the component, and exhibit an excellent stress-relieving effect against external stress. Furthermore, the resin particles according to the embodiment of the present invention may also possess toughness in addition to softness. As a result, when the resin particles according to the embodiment of the present invention are added to a base resin such as a semiconductor component, toughness can be imparted to the component, and its strength can be improved. Therefore, the resin particles according to the embodiment of the present invention can be used as a stress-relieving agent.

[0013] The resin particles according to the embodiment of the present invention have a dielectric loss tangent of 0.0050 or less at a measurement frequency of 10 GHz. Thus, because the resin particles according to the embodiment of the present invention have a low dielectric loss tangent, the resin containing the resin particles can exhibit excellent dielectric properties. Examples of excellent dielectric properties include a low dielectric constant and a low dielectric loss tangent.

[0014] As described above, the resin particles according to the embodiments of the present invention have flexibility and excellent dielectric properties, and in addition to stress relaxation of resins mixed with resin particles, it is also possible to improve dielectric properties such as lower dielectric constant and lower dielectric loss tangent, making them suitable as stress relaxants to be added to resin compositions for semiconductor materials, for example.

[0015] The glass transition temperature of resin particles can be measured using a differential scanning calorimeter (DSC) according to the method described in JIS K7121:1987, 2012 "Method for Measuring the Transition Temperature of Plastics".

[0016] In order to better exhibit the effects of the present invention, the first glass transition temperature is preferably -40.0°C to -25.0°C, more preferably -40.0°C to -27.0°C, even more preferably -40.0°C to -30.0°C, and particularly preferably -39.0°C to -32.0°C.

[0017] In order to better exhibit the effects of the present invention, the second glass transition temperature is preferably 100.0°C to 135.0°C, more preferably 105.0°C to 135.0°C, and even more preferably 110.0°C to 130.0°C.

[0018] The resin particles according to the embodiment of the present invention may have one glass transition temperature (only a first glass transition temperature) as a glass transition temperature of -40.0°C to -20.0°C, or may have multiple glass transition temperatures. The resin particles according to the embodiment of the present invention may have one glass transition temperature (only a second glass transition temperature) as a glass transition temperature of 100°C to 140°C, or may have multiple glass transition temperatures.

[0019] The resin particles according to the embodiments of the present invention have a dielectric loss tangent at a frequency of 10 GHz, preferably 0.0040 or less, more preferably 0.0030 or less, even more preferably 0.0020 or less, particularly preferably 0.0015 or less, and most preferably 0.0011 or less. The lower limit of the dielectric loss tangent may preferably be 0 or more.

[0020] The average particle size of the resin particles according to the embodiments of the present invention is preferably 0.1 μm to 10.0 μm, more preferably 0.1 μm to 5.0 μm or less, and even more preferably 0.1 μm to 1.0 μm. Resin particles having such an average particle size are suitable, for example, for thinning semiconductor components.

[0021] The average particle diameter of the resin particles according to the embodiments of the present invention is preferably 100 nm to 900 nm, more preferably 200 nm to 850 nm, and even more preferably 250 nm to 800 nm. If the average particle diameter of the resin particles according to the embodiments of the present invention is within the above range, it is more suitable for thinning semiconductor components.

[0022] The resin particles according to the embodiments of the present invention are typically solid particles. If the resin particles according to the embodiments of the present invention are solid particles, they can exhibit better flexibility.

[0023] The resin particles according to embodiments of the present invention typically include a polymer P obtained by the reaction of a composition C containing a monomer component (M). The monomer component (M) is a radical polymerizable monomer, preferably a vinyl monomer, and more preferably a crosslinkable monomer (a) and a monofunctional monomer (b). Therefore, a preferred embodiment of polymer P includes structural units derived from the crosslinkable monomer (a) and structural units derived from the monofunctional monomer (b). By including such a polymer P, the effects of the present invention can be more fully expressed.

[0024] Polymer P may be of one type or of two or more types.

[0025] The content ratio of polymer P in the resin particles according to the embodiments of the present invention is preferably 60% to 100% by weight, more preferably 70% to 100% by weight, even more preferably 80% to 100% by weight, even more preferably 90% to 100% by weight, particularly preferably 95% to 100% by weight, and most preferably 98% to 100% by weight, in order to better express the effects of the present invention.

[0026] The crosslinkable monomer (a) has two or more double bonds in its molecule. Examples of crosslinkable monomers (a) include polyfunctional (meth)acrylic acid esters such as ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, and glycerin tri(meth)acrylate; polyfunctional acrylamide derivatives such as N,N'-methylenebis(meth)acrylamide and N,N'-ethylenebis(meth)acrylamide; polyfunctional allyl derivatives such as diallylamine and tetraallyloxyethane; and aromatic crosslinkable monomers such as divinylbenzene, divinylnaphthalene, diallyl phthalate, and divinylbiphenyl. In terms of being able to better express the effects of the present invention, aromatic crosslinkable monomers are preferred as crosslinkable monomer (a), and divinylbenzene is more preferred. There may be only one crosslinkable monomer (a) or there may be two or more.

[0027] Monofunctional monomer (b) has one double bond in its molecule. Examples of monofunctional monomers (b) include aromatic monofunctional monomers such as styrene, α-methylstyrene, ethyl vinylbenzene, vinyltoluene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, vinyl biphenyl, and vinylnaphthalene; alkyl (meth)acrylic acid esters having 1 to 16 carbon atoms such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and cetyl (meth)acrylate; carboxyl group-containing hydrophilic monomers such as (meth)acrylic acid, 2-methacryloyloxyethyl succinic acid, 2-methacryloyloxyethyl phthalic acid, 2-methacryloyloxyethyl hexahydrophthalic acid, 2-methacryloyloxyethyl maleic acid, 2-acryloyloxyethyl hexahydrophthalic acid, 2-acryloyloxyethyl succinic acid, and 2-acryloyloxyethyl phthalic acid; and epoxy group-containing (meth)acrylic acid esters such as glycidyl (meth)acrylate. In order to better express the effects of the present invention, it is preferable that monofunctional monomer (b) includes an aromatic monofunctional monomer. The aromatic monofunctional monomer is preferably styrene or ethyl vinylbenzene. Monofunctional monomer (b) may be one type or two or more types.

[0028] The total content ratio of the crosslinkable monomer (a) and monofunctional monomer (b) in the monomer component (M) is preferably 50 to 100 parts by weight, more preferably 80 to 100 parts by weight, even more preferably 90 to 100 parts by weight, and particularly preferably 95 to 100 parts by weight, when the monomer component (M) is 100 parts by weight, in order to better express the effects of the present invention. The total content ratio of the aromatic crosslinkable monomer and aromatic monofunctional monomer in the monomer component (M) is preferably 50 to 100 parts by weight, more preferably 80 to 100 parts by weight, even more preferably 90 to 100 parts by weight, and particularly preferably 95 to 100 parts by weight, when the monomer component (M) is 100 parts by weight, in order to better express the effects of the present invention.

[0029] In order to better express the effects of the present invention, the content ratio of the crosslinkable monomer (a) in the monomer component (M) is preferably 1 to 30 parts by weight, more preferably 2 to 20 parts by weight, and even more preferably 3 to 10 parts by weight, when the monomer component (M) is 100 parts by weight.

[0030] In order to better exhibit the effects of the present invention, the content of aromatic crosslinkable monomers in monomer component (M) is preferably 1 to 30 parts by weight, more preferably 2 to 20 parts by weight, and even more preferably 3 to 10 parts by weight, when monomer component (M) is 100 parts by weight.

[0031] In order to better express the effects of the present invention, the content ratio of monofunctional monomer (b) in monomer component (M) is preferably 20 to 99 parts by weight, more preferably 40 to 99 parts by weight, even more preferably 50 to 99 parts by weight, even more preferably 70 to 99 parts by weight, particularly preferably 80 to 98 parts by weight, and most preferably 90 to 97 parts by weight, when monomer component (M) is 100 parts by weight.

[0032] In order to better express the effects of the present invention, the content of aromatic monofunctional monomers in monomer component (M) is preferably 20 to 99 parts by weight, more preferably 40 to 99 parts by weight, even more preferably 50 to 99 parts by weight, particularly preferably 70 to 99 parts by weight, and most preferably 80 to 98 parts by weight, when monomer component (M) is 100 parts by weight.

[0033] In order to better exhibit the effects of the present invention, the content of (meth)acrylic monomers in monomer component (M) is preferably 0 to 20 parts by weight, more preferably 0 to 15 parts by weight, and even more preferably 0 to 10 parts by weight, when monomer component (M) is 100 parts by weight. This makes it possible to realize resin particles with excellent dielectric properties. In this specification, (meth)acrylic monomer means monomer having a (meth)acryloyl group. The (meth)acrylic monomer may contain methyl (meth)acrylate, 2-methacryloyloxyethyl succinic acid, or glycidyl (meth)acrylate, and may contain methyl (meth)acrylate. As the (meth)acrylic monomer, in addition to methyl (meth)acrylate, the (meth)acrylic monomer may contain a reactive group (glycidyl group, carboxyl group) such as 2-methacryloyloxyethyl succinic acid or glycidyl (meth)acrylate. The inclusion of reactive groups in (meth)acrylic monomers improves their affinity with the base resin, which can lead to improved adhesion and mechanical strength in components containing resin particles.

[0034] The monomer component (M) may include, in addition to the above-described crosslinkable monomer (a) and monofunctional monomer (b), any other monomer of appropriate reactivity. The other monomer may be one type or two or more types.

[0035] The content of monomer component (M) in composition C is preferably 70% by weight or more and less than 100% by weight, more preferably 75% by weight to 99% by weight, even more preferably 80% by weight to 98% by weight, particularly preferably 85% by weight to 97% by weight, and most preferably 85% by weight to 95% by weight. If the content of monomer component (M) in composition C is too low and outside the above range, the effects of the present invention may not be realized, for example, excellent dielectric properties may not be realized. Herein, in the present invention, the monomer component (M) does not include polymerization initiators and surfactants used in the polymerization reaction.

[0036] In embodiments of the present invention, composition C typically includes a soft component (S) in addition to a monomer component (M). The soft component (S) is preferably a reactive soft component that reacts with the monomer component (M). The reactive soft component preferably has a radical reactive group, and for example, includes a double bond. The resin particles according to embodiments of the present invention can have excellent flexibility by containing a polymer P obtained by the reaction of composition C containing such a soft component (S).

[0037] The reactive flexible component preferably includes a polymer of a conjugated diolefin monomer. Examples of polymers of conjugated diolefin monomers include polybutadiene and polyisoprene. The reactive flexible component preferably includes polybutadiene. The polybutadiene may be partially hydrogenated polybutadiene. The hydrogenation rate of the partially hydrogenated polybutadiene may be 30% to 90% or 50% to 85%. Such a configuration can further enhance the effects of the present invention.

[0038] The soft component (S) may include thermoplastic elastomers in addition to those described above. Examples of thermoplastic elastomers include styrene-butadiene-styrene copolymers, hydrogenated styrene-butadiene-styrene copolymers, styrene-ethylene-propylene-styrene block copolymers, styrene-ethylene-butene-styrene copolymers, styrene-isoprene-styrene block copolymers, styrene-isobutylene-styrene copolymers, and styrene-isobutylene copolymers. The thermoplastic elastomer is preferably a block copolymer.

[0039] The block copolymer is preferably reactive with the monomer component (M). That is, the reactive soft component may further contain a block copolymer in addition to those described above, and may further contain a block copolymer that is a thermoplastic elastomer. Examples of such block copolymers include polymers having a polymer block of a vinyl monomer and a polymer block of a conjugated diolefin monomer. The vinyl monomer is preferably an aromatic vinyl monomer. Examples of such block copolymers include styrene-butadiene-styrene block copolymers, styrene-isoprene-styrene block copolymers, methylene methacrylate-butadiene-styrene copolymers, and hydrogenated versions thereof, preferably styrene-butadiene-styrene block copolymers, styrene-isoprene-styrene block copolymers, and hydrogenated versions thereof, and more preferably styrene-butadiene-styrene block copolymers and hydrogenated versions thereof.

[0040] Therefore, the reactive soft component may, in some cases, include polymers of conjugated diolefin monomers and polymers having polymer blocks of vinyl monomers and polymer blocks of conjugated diolefin monomers, and may also include polybutadiene and styrene-butadiene-styrene block polymers.

[0041] In order to better exhibit the effects of the present invention, when the total amount of monomer component (M) and reactive soft component is 100 parts by weight, the crosslinkable monomer (a) is preferably 0 to 30 parts by weight, more preferably greater than 0 parts by weight and 30 parts by weight or less, even more preferably 1 to 30 parts by weight, particularly preferably 2 to 20 parts by weight, and most preferably 3 to 10 parts by weight.

[0042] In terms of being able to more effectively exhibit the effects of the present invention, when the total of the monomer component (M) and the reactive soft component is 100 parts by weight, the aromatic crosslinkable monomer is preferably 0 parts by weight to 30 parts by weight or less, more preferably more than 0 parts by weight and 30 parts by weight or less, still more preferably 1 part by weight to 30 parts by weight, still more preferably 1.5 parts by weight to 20 parts by weight, particularly preferably 2 parts by weight to 10 parts by weight, and most preferably 2 parts by weight to 7 parts by weight.

[0043] In terms of being able to more effectively exhibit the effects of the present invention, when the total of the monomer component (M) and the reactive soft component is 100 parts by weight, the monofunctional monomer (b) is preferably 20 parts by weight or more, more preferably 40 parts by weight to 99 parts by weight, still more preferably 50 parts by weight to 98 parts by weight, still more preferably 70 parts by weight to 97 parts by weight, still more preferably 75 parts by weight to 96 parts by weight, particularly preferably 78 parts by weight to 95 parts by weight, and most preferably 80 parts by weight to 93 parts by weight.

[0044] In terms of being able to more effectively exhibit the effects of the present invention, when the total of the monomer component (M) and the reactive soft component is 100 parts by weight, the aromatic monofunctional monomer is preferably 20 parts by weight or more, more preferably 40 parts by weight to 99 parts by weight, still more preferably 50 parts by weight to 98 parts by weight, still more preferably 70 parts by weight to 97 parts by weight, still more preferably 75 parts by weight to 96 parts by weight, particularly preferably 78 parts by weight to 95 parts by weight, and most preferably 80 parts by weight to 93 parts by weight.

[0045] In order to better express the effects of the present invention, when the total amount of monomer component (M) and reactive soft component is 100 parts by weight, the reactive soft component is preferably greater than 0 parts by weight and 30 parts by weight or less, more preferably 1 to 25 parts by weight, even more preferably 2 to 20 parts by weight, particularly preferably 3 to 15 parts by weight, and most preferably 5 to 15 parts by weight. In order to better express the effects of the present invention, when the total amount of monomer component (M) and reactive soft component is 100 parts by weight, the polybutadiene is preferably greater than 0 parts by weight and 30 parts by weight or less, more preferably 1 to 25 parts by weight, even more preferably 2 to 20 parts by weight, particularly preferably 3 to 20 parts by weight, and most preferably 5 to 20 parts by weight.

[0046] In order to better exhibit the effects of the present invention, when the total amount of monomer component (M) and reactive soft component is 100 parts by weight, the (meth)acrylic compound is preferably 0 parts by weight or more and less than 20 parts by weight, more preferably 0 to 15 parts by weight, and even more preferably 0 to 10 parts by weight. This makes it possible to realize resin particles with excellent dielectric properties. In this specification, (meth)acrylic compound means a compound having a (meth)acryloyl group. (Meth)acrylic compound also includes (meth)acrylic monomers.

[0047] ≪≪Applications of Resin Particles≫≫ The resin particles according to the embodiments of the present invention can be used in various applications. In addition to their use in resin compositions for semiconductor components, the resin particles according to the embodiments of the present invention can be applied to applications that can utilize the effects of the present invention, such as paint compositions, heat-insulating resin compositions, light-diffusing resin compositions, and light-diffusing films. In terms of being able to better utilize the effects of the present invention, the resin particles according to the embodiments of the present invention are suitable for semiconductor components, and are particularly suitable for use in resin compositions for semiconductor components. Since the resin particles according to the embodiments of the present invention are flexible and have excellent dielectric properties, they can improve dielectric properties while relieving stress in semiconductor components. Furthermore, since the resin particles according to the embodiments of the present invention are tough in addition to flexible, they can be used as a stress reliever not only for semiconductor components but also for general resins.

[0048] A semiconductor member means a member constituting a semiconductor, and examples thereof include a semiconductor package and a semiconductor module. In this specification, the resin composition for semiconductor members means a resin composition used for semiconductor members.

[0049] A semiconductor package has an IC chip as an essential constituent member, and is composed of using at least one member selected from molding resins, underfill materials, mold underfill materials, die bonding materials, prepregs for semiconductor package substrates, metal-clad laminates for semiconductor package substrates, and build-up materials for printed circuit boards for semiconductor packages.

[0050] A semiconductor module has a semiconductor package as an essential constituent member, and is composed of using at least one member selected from prepregs for printed circuit boards, metal-clad laminates for printed circuit boards, build-up materials for printed circuit boards, solder resist materials, coverlay films, electromagnetic wave shielding films, and adhesive sheets for printed circuit boards.

[0051] The resin composition for semiconductor members according to an embodiment of the present invention contains resin particles according to an embodiment of the present invention, and typically contains resin particles and a resin component according to an embodiment of the present invention.

[0052] As the resin component, any appropriate resin component adopted for semiconductor members can be adopted. Such resin components are preferably insulating resins, and examples thereof include polyphenylene ether, polyphenylene sulfide, polyimide, polyetherimide, polybismaleimide, polyarylate, epoxy resin, polyester resin, urethane resin, acrylic resin, cyanate resin, phenol resin, polystyrene resin, fluorine resins such as PTFE, and cycloolefin resin.

[0053] The content ratio of the resin particles according to an embodiment of the present invention in the resin composition for semiconductor members according to an embodiment of the present invention can be appropriately set according to the purpose.

[0054] <<Method for producing resin particles>> Resin particles according to the embodiment of the present invention can be produced, for example, by the polymerization reaction of composition C described above.

[0055] A method for producing resin particles according to embodiments of the present invention typically includes a two-step polymerization process consisting of a first polymerization step and a second polymerization step. In the first polymerization step, a composition C1 containing a first monomer component (M1) and a soft component (S) is subjected to a suspension polymerization reaction. In the second polymerization step, the product obtained in the first polymerization step is subjected to an emulsion polymerization reaction with a second monomer component (M2). Typically, the first monomer component (M1) includes a crosslinkable monomer (a1) and a monofunctional monomer (b1), and the second monomer component (M2) includes a crosslinkable monomer (a2) and a monofunctional monomer (b2).

[0056] Suspension polymerization is a polymerization method in which monomers and an aqueous medium are mechanically stirred to suspend the monomers in the aqueous medium and polymerize them.

[0057] Emulsion polymerization is a polymerization method in which a liquid medium, a monomer component that is poorly soluble in the medium, and a surfactant are mixed, and a polymerization initiator that is soluble in the medium is added to carry out polymerization.

[0058] It is preferable that the first and second polymerization steps be carried out in a single reactor. Therefore, it is preferable that the second polymerization step be carried out in the same reactor as the first polymerization step, and more preferably that it be carried out immediately after the first polymerization step in the same reactor in which the first polymerization step was carried out. Here, carrying out the first and second polymerization steps consecutively means, for example, that after the suspension polymerization in the first polymerization step, the second polymerization step is carried out without removing the product from the reactor and / or without intentionally lowering the temperature of the reactor (i.e., without cooling the product of the first polymerization step).

[0059] <First Polymerization Step> In the first polymerization step, the oil phase containing composition C1 and the aqueous phase are mechanically stirred to disperse the oil phase in the aqueous phase, and a polymerization reaction is carried out to produce a product containing a polymer. The above product is typically used as seed particles in the second polymerization step.

[0060] Composition C1 comprises a monomer component (M1) containing a crosslinkable monomer (a1) and a monofunctional monomer (b1), and a softening component (S). This allows for the production of resin particles with soft properties.

[0061] The crosslinkable monomer (a1) preferably includes an aromatic crosslinkable monomer, and more preferably consists only of an aromatic crosslinkable monomer. The crosslinkable monomer (a1) is, for example, a monomer listed as a crosslinkable monomer in the above-mentioned resin particles. The aromatic crosslinkable monomer is, for example, a monomer listed as an aromatic crosslinkable monomer in the above-mentioned resin particles. The aromatic crosslinkable monomer is preferably divinylbenzene. The crosslinkable monomer (a1) may be one type or two or more types.

[0062] The monofunctional monomer (b1) preferably includes an aromatic monofunctional monomer, and more preferably consists only of an aromatic monofunctional monomer. The monofunctional monomer (b1) is, for example, the monomer listed as a monofunctional monomer in the above-mentioned resin particles. The aromatic monofunctional monomer is, for example, the monomer listed as an aromatic monofunctional monomer in the above-mentioned resin particles. The aromatic monofunctional monomer is preferably styrene or ethyl vinylbenzene. The monofunctional monomer (b1) may consist of only one type or two or more types.

[0063] The total content ratio of the crosslinkable monomer (a1) and monofunctional monomer (b1) in the monomer component (M1) is preferably 50 to 100 parts by weight, more preferably 80 to 100 parts by weight, even more preferably 90 to 100 parts by weight, and particularly preferably 95 to 100 parts by weight, when the monomer component (M) is 100 parts by weight, in order to better express the effects of the present invention. The total content ratio of the aromatic crosslinkable monomer and aromatic monofunctional monomer in the monomer component (M1) is preferably 50 to 100 parts by weight, more preferably 80 to 100 parts by weight, even more preferably 90 to 100 parts by weight, and particularly preferably 95 to 100 parts by weight, when the monomer component (M) is 100 parts by weight, in order to better express the effects of the present invention.

[0064] In order to better express the effects of the present invention, the content of the crosslinkable monomer (a1) in the monomer component (M1) is preferably greater than 0 parts by weight and 30 parts by weight or less, more preferably 1 to 30 parts by weight, even more preferably 2 to 20 parts by weight, and particularly preferably 3 to 10 parts by weight, when the monomer component (M1) is 100 parts by weight. In order to better express the effects of the present invention, the content of the aromatic crosslinkable monomer in the monomer component (M1) is preferably greater than 0 parts by weight and 30 parts by weight or less, when the monomer component (M) is 100 parts by weight, more preferably 1 to 30 parts by weight, even more preferably 2 to 20 parts by weight, and particularly preferably 3 to 10 parts by weight.

[0065] In order to better express the effects of the present invention, the content of monofunctional monomer (b1) in monomer component (M1) is preferably 20 to 99 parts by weight, more preferably 40 to 99 parts by weight, even more preferably 50 to 99 parts by weight, even more preferably 70 to 99 parts by weight, particularly preferably 80 to 98 parts by weight, and most preferably 90 to 97 parts by weight, when monomer component (M1) is 100 parts by weight. In order to better express the effects of the present invention, the content of aromatic monofunctional monomer in monomer component (M1) is preferably 20 to 99 parts by weight, more preferably 40 to 99 parts by weight, even more preferably 50 to 99 parts by weight, particularly preferably 70 to 99 parts by weight, and most preferably 80 to 98 parts by weight, when monomer component (M) is 100 parts by weight.

[0066] The explanation for the flexible component (S) can be directly applied as described in the section on "Resin Particles". The flexible component (S) preferably includes a reactive flexible component. The reactive flexible component preferably includes polybutadiene. The polybutadiene may be partially hydrogenated polybutadiene. With this configuration, the effects of the present invention can be more fully expressed.

[0067] In order to better express the effects of the present invention, when the total amount of monomer component (M1) and reactive soft component is 100 parts by weight, the crosslinkable monomer (a1) is preferably greater than 0 parts by weight and 30 parts by weight or less, more preferably 1 to 30 parts by weight, more preferably 2 to 20 parts by weight, and even more preferably 3 to 10 parts by weight. In order to better express the effects of the present invention, when the total amount of monomer component (M1) and reactive soft component is 100 parts by weight, the aromatic crosslinkable monomer is preferably greater than 0 parts by weight and 30 parts by weight or less, more preferably 1 to 30 parts by weight, more preferably 2 to 20 parts by weight, and even more preferably 3 to 10 parts by weight.

[0068] In order to better express the effects of the present invention, when the total amount of monomer component (M1) and reactive soft component is 100 parts by weight, the monofunctional monomer (b1) is preferably 20 parts by weight or more, more preferably 40 to 99 parts by weight, even more preferably 50 to 98 parts by weight, even more preferably 70 to 97 parts by weight, particularly preferably 75 to 95 parts by weight, and most preferably 80 to 90 parts by weight. In order to better express the effects of the present invention, when the total amount of monomer component (M1) and reactive soft component is 100 parts by weight, the aromatic monofunctional monomer is preferably 20 parts by weight or more, more preferably 40 to 99 parts by weight, even more preferably 50 to 98 parts by weight, even more preferably 70 to 97 parts by weight, particularly preferably 75 to 95 parts by weight, and most preferably 80 to 90 parts by weight.

[0069] In order to better express the effects of the present invention, when the total amount of monomer component (M1) and reactive soft component is 100 parts by weight, the reactive soft component is preferably greater than 0 parts by weight and 30 parts by weight or less, more preferably 1 to 25 parts by weight, even more preferably 2 to 20 parts by weight, particularly preferably 3 to 15 parts by weight, and most preferably 5 to 15 parts by weight. In order to better express the effects of the present invention, when the total amount of monomer component (M1) and reactive soft component is 100 parts by weight, the polybutadiene is preferably greater than 0 parts by weight and 30 parts by weight or less, more preferably 1 to 25 parts by weight, even more preferably 2 to 20 parts by weight, particularly preferably 3 to 15 parts by weight, and most preferably 5 to 15 parts by weight.

[0070] In order to better exhibit the effects of the present invention, when the total amount of monomer component (M1) and reactive soft component is 100 parts by weight, the (meth)acrylic compound is preferably 0 parts by weight or more and less than 20 parts by weight, more preferably 0 to 15 parts by weight, even more preferably 0 to 10 parts by weight, particularly preferably 0 to 5 parts by weight, and most preferably 0 parts by weight. This makes it possible to obtain resin particles with excellent dielectric properties.

[0071] In addition to the components described above, the oil phase may contain any other suitable components as long as they do not impair the effects of the present invention.

[0072] The aqueous phase typically includes water-based solvents. Typical examples of water-based solvents include water and mixed solvents of water and lower alcohols (methanol, ethanol, etc.).

[0073] In the first polymerization step, the amount of aqueous solvent used can be any appropriate amount, as long as it does not impair the effects of the present invention. The amount of aqueous solvent used in the first polymerization step is preferably 10 to 5000 parts by weight, more preferably 50 to 3000 parts by weight, and even more preferably 100 to 2000 parts by weight, when composition C1 is 100 parts by weight.

[0074] In addition to the components described above, the aqueous phase may contain any other suitable components as long as they do not impair the effects of the present invention.

[0075] In the first polymerization step, when carrying out the reaction of composition C1, any suitable additive that does not fall under either the monomer component (M) or the softening component (S) may be used, as long as it does not impair the effects of the present invention. Examples of additives include polymerization initiators, surfactants, and dispersion stabilizers.

[0076] Any suitable polymerization initiator can be used as the polymerization initiator, as long as it does not impair the effects of the present invention. Examples of polymerization initiators include organic peroxides such as cumene hydroperoxide, di-tert-butyl peroxide, dicumyl peroxide, benzoyl peroxide, orthochlorobenzoyl peroxide, orthomethoxybenzoyl peroxide, lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, dimethylbis(tert-butylperoxy)hexane, dimethylbis(tert-butylperoxy)hexyn-3, bis(tert-butylperoxyisopropyl)benzene, bis(tert-butylperoxy)trimethylcyclohexane, butyl-bis(tert-butylperoxy)valerate, tert-butyl 2-ethylhexaneperoxyate, dibenzoyl peroxide, paramentane hydroperoxide, tert-butylperoxybenzoate, etc.; 2,2'-azobibisisobutyronitrile, 2,2'-azobi Azobis(2-methylbutyronitrile), 2,2'-azobis(2-isopropylbutyronitrile), 2,2'-azobis(2,3-dimethylbutyronitrile), 2,2'-azobis(2,4-dimethylbutyronitrile), 2,2'-azobis(2-methylcapronitrile), 2,2'-azobis(2,3,3-trimethylbutyronitrile), 2,2'-azobis(2,4,4-trimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile) Examples of azo compounds include lelonitrile, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(4-ethoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(4-n-butoxy-2,4-dimethylvaleronitrile), 1,1'-azobis(cyclohexane-1-carbonitride), 2-(carbamoylazo)isobutyronitrile, and 4,4'-azobis(4-cyanopentanoic acid). Polymerization initiators may be used individually or in combination of two or more.

[0077] The amount of polymerization initiator used in the first polymerization step (the amount added during the first polymerization step) is preferably 0.01 to 10 parts by weight, and more preferably 0.1 to 5 parts by weight, when the total amount of monomer components (M1) and reactive soft components is 100 parts by weight.

[0078] Polymerization initiators are typically added to the oil phase.

[0079] As the surfactant, any suitable surfactant can be used as long as it does not impair the effects of the present invention. There may be only one type of surfactant or two or more types. Examples of such surfactants include anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants.

[0080] Examples of anionic surfactants include sodium oleate; fatty acid soaps such as potassium castor oil soap; polysulfonates; polycarboxylates; alkyl sulfate esters such as sodium lauryl sulfate and ammonium lauryl sulfate; alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate; alkylaryl sulfonates; alkylnaphthalene sulfonates; alkanesulfonates; dialkyl sulfonates; dialkyl sulfosuccinates; alkyl phosphates; alkyl phosphate esters; naphthalene sulfonic acid formalin condensates or their salts, such as sodium salts of β-naphthalene sulfonic acid formalin condensates; and polyoxyethylene nonylphenyl Examples include polyoxyethylene alkylphenyl ether sulfates such as ether sulfates (commercial products include, for example, Newcol 707-SF manufactured by Nippon Emulsifier Co., Ltd.); polyoxyethylene sulfonated phenyl ether phosphate; polyoxyethylene alkyl ether sulfates such as sodium polyoxyethylene lauryl ether sulfate and ammonium polyoxyethylene lauryl ether sulfate; polyoxyethylene alkyl sulfates; polyoxyethylene alkyl phosphate sulfonates; glycerol borate fatty acid esters; polyoxyethylene glycerol fatty acid esters; phosphate ester surfactants; and phosphite ester surfactants. The anionic surfactant may be one type or two or more types. Furthermore, the countercation of the anionic group is preferably an ammonium salt.

[0081] Examples of cationic surfactants include alkylamine salts such as laurylamine acetate and stearylamine acetate; and quaternary ammonium salts such as lauryltrimethylammonium chloride. There may be only one cationic surfactant or two or more.

[0082] Examples of nonionic surfactants include (meth)acrylate sulfate surfactants (commercial products such as RMA-564, RMA-568, and RMA-1114 from Nippon Emulsifier Co., Ltd.); polyoxyalkylene branched decyl ethers; polyoxyalkylene alkyl ethers such as polyoxyethylene tridecyl ether, polyoxyethylene isodecyl ether, polyoxyethylene lauryl ether, and polyoxyethylene oleyl cetyl ether; polyoxyalkylene aryl ethers such as polyoxyethylene naphthyl ether and polyoxyethylene phenyl ether; polyoxyalkylene alkylaryl ethers; polyether polyols; polyoxyethylene styrene-phenyl ether; polyoxyethylene polyoxypropylene glycol; polyoxyethylene glyceryl isostearate; polyoxyethylene fatty acid esters; sorbitan fatty acid esters; polyoxysorbitan fatty acid esters; polyoxyethylene alkylamines; glycerin fatty acid esters; and oxyethylene-oxypropylene block polymers. The nonionic surfactant may be one type or two or more types.

[0083] Examples of amphoteric surfactants include lauryldimethylamine oxide, alkyldiaminoethylglycine hydrochloride, sodium laurylaminopropionate, and alkylbetaine. The amphoteric surfactant may be present in a single form or in two or more forms.

[0084] A reactive surfactant may be used as the surfactant. A reactive surfactant is a surfactant having a radical reactive group, such as a surfactant having a vinyl group. There may be only one type of reactive surfactant or two or more types. When a reactive surfactant is used, the surfactant can be incorporated into the polymer, so the surfactant can be effectively distributed unevenly on the particle surface during suspension polymerization, and the surfactant effect can be improved. As a result, an excellent surfactant effect can be obtained, particle aggregation and coalescence during manufacturing can be suppressed, the generation of substandard particles as by-products can be reduced, and more uniform dielectric properties can be exhibited.

[0085] Examples of reactive surfactants include anionic surfactants having a vinyl group and nonionic surfactants having a vinyl group.

[0086] Examples of anionic surfactants having a vinyl group include polyoxyethylene-1-(allyloxymethyl)alkyl ether sulfate ammonium, polyoxyethylene styrene-propenylphenyl ether sulfate ammonium, polyoxyalkylene alkenyl ether sulfate ammonium, α-sulfo-ω-(1-alkoxymethyl-2-(2-propenyloxy)ethoxy)-poly(oxy-1,2-ethanediyl)ammonium, polyoxypropylene allyl ether phosphate, and bis(polyoxyethylene phenyl ether) methacrylate sulfate. Furthermore, ammonium salts are preferred as the countercation of the anionic group. By using such surfactants, the average particle size of the resin particles can be reduced. In addition, the amount of metal residue can be reduced.

[0087] Examples of commercially available polyoxyethylene-1-(allyloxymethyl)alkyl ether sulfate ammonium products include the trade names "Aqualon KH-10" and "Aqualon KH-1025" (a 25% by weight aqueous solution of "Aqualon KH-10") manufactured by Daiichi Kogyo Seiyaku Co., Ltd.

[0088] Examples of commercially available polyoxyethylene styrene-propenylphenyl ether sulfate ammonium products include the product names "Aqualon AR-10," "Aqualon AR-20," "Aqualon AR-3025" (a 25% by weight aqueous solution of "Aqualon AR-30"), and "Aqualon AR-1025" (a 25% by weight aqueous solution of "Aqualon AR-10"), all manufactured by Daiichi Kogyo Seiyaku Co., Ltd.

[0089] A commercially available product containing polyoxyalkylene alkenyl ether ammonium sulfate is, for example, "Latemul PD-104" manufactured by Kao Corporation.

[0090] Examples of commercially available α-sulfo-ω-(1-alkoxymethyl-2-(2-propenyloxy)ethoxy)-poly(oxy-1,2-ethanediyl)ammonium products include "Adekaria Soap SR-10" and "Adekaria Soap SR-20" manufactured by ADEKA Corporation.

[0091] A commercially available product containing polyoxypropylene allyl ether phosphate is, for example, "Adekaria Soap PP-70" manufactured by ADEKA Corporation.

[0092] A commercially available product containing bis(polyoxyethylene phenyl ether) methacrylate sulfate is, for example, "Antox MS-60" manufactured by Nippon Emulsifier Co., Ltd.

[0093] Examples of nonionic surfactants having a vinyl group include polyoxyethylene styrene-propenylphenyl ether, polyoxyethylene-1-(allyloxymethyl) alkyl ether, and polyoxyalkylene alkenyl ether.

[0094] Examples of commercially available polyoxyethylene styrene-propenylphenyl ethers include the product names "Aqualon AN-10," "Aqualon AN-20," "Aqualon AN-30," and "Aqualon AN-5065" manufactured by Daiichi Kogyo Seiyaku Co., Ltd.

[0095] Examples of commercially available polyoxyethylene-1-(allyloxymethyl)alkyl ethers include the product names "Aqualon KN-10," "Aqualon KN-20," "Aqualon KN-30," and "Aqualon KN-5065" manufactured by Daiichi Kogyo Seiyaku Co., Ltd., and the product names "Adekaria Soap ER-10," "Adekaria Soap ER-20," "Adekaria Soap ER-30," and "Adekaria Soap ER-40" manufactured by ADEKA Corporation.

[0096] Examples of commercially available polyoxyalkylene alkenyl ethers include the product names "Latemul PD-420," "Latemul PD-430," and "Latemul PD-450" manufactured by Kao Corporation.

[0097] Surfactants are typically added to the aqueous phase.

[0098] In the first polymerization step, the amount of surfactant used can be any appropriate amount, as long as it does not impair the effects of the present invention. The amount of surfactant used in the first polymerization step is preferably 0.001 to 5 parts by weight, more preferably 0.005 to 3 parts by weight, and even more preferably 0.01 to 1 part by weight, per 100 parts by weight of the aqueous phase.

[0099] As a dispersion stabilizer, any suitable dispersion stabilizer can be used as long as it does not impair the effects of the present invention. There may be only one dispersion stabilizer or two or more. Examples of dispersion stabilizers that can better express the effects of the present invention include: polyvinyl alcohol; polycarboxylic acid; celluloses such as hydroxyethylcellulose and carboxymethylcellulose; inorganic water-soluble polymers such as polyvinylpyrrolidone and sodium tripolyphosphate; phosphates such as calcium phosphate, magnesium phosphate, aluminum phosphate, and zinc phosphate; pyrophosphates such as calcium pyrophosphate, magnesium pyrophosphate, aluminum pyrophosphate, and zinc pyrophosphate; and poorly water-soluble inorganic compounds such as calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, and colloidal silica. Among these, magnesium pyrophosphate is preferred in that it can better express the effects of the present invention.

[0100] Dispersion stabilizers may be added to the aqueous phase or the oil phase, but they are typically added to the aqueous phase.

[0101] The amount of dispersion stabilizer used is preferably 0 to 50 parts by weight, and more preferably 0 to 10 parts by weight, per 100 parts by weight of the aqueous solvent contained in the aqueous phase.

[0102] The dispersion of the oil phase into the aqueous phase can be carried out using any suitable dispersion method, as long as it allows the oil phase to exist in droplet form within the aqueous phase, without impairing the effects of the present invention. Typical dispersion methods include those using homogenizers, such as ultrasonic homogenizers and high-pressure homogenizers.

[0103] Any suitable suspension polymerization method can be employed, as long as it does not impair the effects of the present invention.

[0104] The polymerization temperature in the first polymerization step can be any suitable polymerization temperature, as long as it is suitable for suspension polymerization and does not impair the effects of the present invention. For example, such polymerization temperatures are 30°C to 95°C.

[0105] The polymerization time in the first polymerization step can be any appropriate polymerization time, as long as it is suitable for suspension polymerization and does not impair the effects of the present invention. Such a polymerization time is preferably 1 to 20 hours.

[0106] <Second Polymerization Step> In the second polymerization step, emulsion polymerization is carried out using the monomer component (M2). In the second polymerization step, the monomer component (M2) is emulsion polymerized in the presence of the product containing the polymer obtained in the first polymerization step. That is, the emulsion polymerization in the second polymerization step is seed emulsion polymerization using the product obtained in the first polymerization step as seed particles. It is preferable that the second polymerization step is carried out by adding the monomer component (M2) to the seed particles obtained in the first polymerization step.

[0107] Seed emulsion polymerization is an emulsion polymerization method in which a liquid medium, a monomer component that is poorly soluble in the medium, and a surfactant are mixed in the presence of seed particles, and a polymerization initiator that is soluble in the medium is added to carry out polymerization.

[0108] The seed particles may be in the form of a dispersion. In the second polymerization step, it is preferable to carry out polymerization by adding a mixture of an oil phase containing a monomer component (M2) and an aqueous phase containing a surfactant to the product obtained in the first polymerization step. In the second polymerization step, it is preferable to carry out seed emulsion polymerization by adding a mixture of an oil phase containing a monomer component (M2) and an aqueous phase containing a surfactant to the reactor used in the first polymerization step, which contains the above product from the first polymerization step.

[0109] The monomer component (2) typically includes a crosslinkable monomer (a2) and a monofunctional monomer (b2).

[0110] The crosslinkable monomer (a2) is the same as the crosslinkable monomer (a) listed in the above-mentioned "<<Resin Particles>>". One type of crosslinkable monomer (a2) may be used alone, or two or more types may be used.

[0111] The monofunctional monomer (b2) is the same as the monofunctional monomer (b) listed in the above-mentioned "<<Resin Particles>>". Monofunctional monomer (b2) may be used alone or in combination of two or more types.

[0112] The total content ratio of crosslinkable monomers (a2) and monofunctional monomers (b2) in the monomer component (M2) is preferably 50 to 100 parts by weight, more preferably 80 to 100 parts by weight, even more preferably 90 to 100 parts by weight, and particularly preferably 95 to 100 parts by weight, when the monomer component (M) is 100 parts by weight, in order to better express the effects of the present invention.

[0113] In order to better express the effects of the present invention, the content ratio of the crosslinkable monomer (a2) in the monomer component (M2) is preferably 1 to 30 parts by weight, more preferably 2 to 20 parts by weight, and even more preferably 3 to 15 parts by weight, when the monomer component (M2) is 100 parts by weight.

[0114] In order to better express the effects of the present invention, the content ratio of monofunctional monomer (b2) in monomer component (M2) is preferably 70 to 99 parts by weight, more preferably 80 to 98 parts by weight, and even more preferably 85 to 97 parts by weight, when the monomer component (M2) is 100 parts by weight.

[0115] The monomer component (M2) is preferably 1 to 100 parts by weight, more preferably 2 to 80 parts by weight, even more preferably 3 to 65 parts by weight, and particularly preferably 5 to 50 parts by weight, when the composition C1 in the first polymerization step is 100 parts by weight.

[0116] In addition to the components described above, the oil phase may contain any other suitable components as long as they do not impair the effects of the present invention.

[0117] The aqueous phase typically contains an aqueous solvent. As the aqueous solvent, the solvent described in the first polymerization step can be used. The amount of aqueous solvent used in the second polymerization step is preferably 10 to 5000 parts by weight, more preferably 50 to 3000 parts by weight, and even more preferably 80 to 1500 parts by weight, per 100 parts by weight of monomer component (M2).

[0118] In addition to the components described above, the aqueous phase may contain any other suitable components as long as they do not impair the effects of the present invention.

[0119] The polymerization initiator used in the second polymerization step can be any suitable polymerization initiator as long as it does not impair the effects of the present invention. Examples of polymerization initiators used in the second polymerization step include water-soluble azo compounds, persulfates (e.g., ammonium persulfate, potassium persulfate, sodium persulfate, etc.), hydrogen peroxide, organic peroxides, and oil-soluble nitrile-azo compounds.

[0120] Polymerization initiators used in the second polymerization step include, for example, 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine]n hydrate (trade name "VA-057"), 4,4'-azobis(4-cyanovaleric acid) (trade name "V-501"), 2,2'-azobis[2-(2-imidazolin-2-yl)propane] and its dihydrochloride salt (trade names "VA-061", "VA-044"), 2,2'-azobis[ 2-methyl-N-(2-hydroxyethyl)propionamide] (product name "VA-086"), 2,2'-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide} (product name "VA-080"), 2,2'-azobis{2-methyl-N-[1,1-bis(hydroxymethyl)ethyl]propionamide} (product name "VA-082"), 2,2'-azobis{2 Water-soluble azo compounds such as {methyl-N-[2-(1-hydroxybutyl)]-propionamide} (trade name "VA-085") (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.); organic peroxides such as cumene hydroperoxide, di-tert-butyl peroxide, dicumyl peroxide, benzoyl peroxide, lauroyl peroxide, dimethylbis(tert-butylperoxy)hexane, dimethylbis(tert-butylperoxy)hexyn-3, bis(tert-butylperoxyisopropyl)benzene, bis(tert-butylperoxy)trimethylcyclohexane, butyl-bis(tert-butylperoxy)valerate, tert-butyl 2-ethylhexaneperoxyate, dibenzoyl peroxide, paramentane hydroperoxide, and tert-butylperoxybenzoate;2,2'-Azobisisobutyronitrile, 2,2'-Azobis(2-methylbutyronitrile), 2,2'-Azobis(2-isopropylbutyronitrile), 2,2'-Azobis(2,3-dimethylbutyronitrile), 2,2'-Azobis(2,4-dimethylbutyronitrile), 2,2'-Azobis(2-methylcapronitrile), 2,2'-Azobis(2,3,3-trimethylbutyronitrile), 2,2'-Azobis(2,4,4-trimethylvaleronitrile), 2,2'-Azobis( Examples include oil-soluble nitrile-azo compounds such as 2,4-dimethylvaleronitrile, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(4-ethoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(4-n-butoxy-2,4-dimethylvaleronitrile), 1,1'-azobis(cyclohexane-1-carbonitride), 2-(carbamoylazo)isobutyronitrile, and 4,4'-azobis(4-cyanopentanoic acid). Furthermore, redox initiators combining the above-mentioned persulfate and organic peroxide polymerization initiators with reducing agents such as sodium sulfoxylate formaldehyde, sodium bisulfite, ammonium bisulfite, sodium thiosulfate, ammonium thiosulfate, hydrogen peroxide, sodium hydroxymethanesulfinate, L-ascorbic acid or its salts, cuprous salts, and ferrous salts may be used as polymerization initiators.

[0121] Among these, 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine]n hydrate (trade name "VA-057"), 4,4'-azobis(4-cyanovaleric acid) (trade name "V-501"), 2,2'-azobis[2-(2-imidazolin-2-yl)propane] (trade name "VA-061"), and 2,2'-azobis[2-methyl-N-(2-hydroxyethyl] ) Propionamide] (Trade name "VA-086"), 2,2'-Azobis{2-methyl-N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]propionamide} (Trade name "VA-080"), 2,2'-Azobis{2-methyl-N-[1,1-bis(hydroxymethyl)ethyl]propionamide} (Trade name "VA-082"), 2,2'-Azobis{2-methyl-N It is preferable to use one or more water-soluble azo compounds such as {2-(1-hydroxybutyl)}-propionamide (trade name "VA-085") (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonnitrile), 4,4'-azobis(4-cyanopentanoic acid), cumene hydroperoxide, di-tert-butyl peroxide, dicumyl peroxide, benzoyl peroxide, and lauroyl peroxide, and it is more preferable to use a water-soluble azo compound. The polymerization initiator may be used alone or in combination of two or more.

[0122] The amount of polymerization initiator used in the second polymerization step (the amount added during the second polymerization step) is preferably 0.01 to 5 parts by weight, more preferably 0.05 to 3 parts by weight, and even more preferably 0.1 to 1 part by weight, per 100 parts by weight of monomer component (M2) in the second polymerization step.

[0123] In the second polymerization step, the aqueous phase preferably contains a polymerization initiator.

[0124] The total amount of polymerization initiator used in the manufacturing method according to the embodiments of the present invention is preferably 0.05 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, and even more preferably 0.2 to 3 parts by weight, when the total amount of monomer component (M1), monomer component (M2), and reactive soft component is 100 parts by weight.

[0125] The surfactant used in the second polymerization step can be any suitable surfactant, as long as it does not impair the effects of the present invention. In the second polymerization step, the surfactant described in the first polymerization step can be used. There may be only one surfactant or two or more surfactants. As the surfactant, the surfactant described in the first polymerization step can be used. In terms of being able to better exhibit the effects of the present invention, it is preferable that the surfactant includes a reactive surfactant.

[0126] The amount of surfactant used in the second polymerization step (the amount added during the second polymerization step) is preferably 0.005 to 5 parts by weight, and more preferably 0.01 to 3 parts by weight, per 100 parts by weight of monomer component (M2).

[0127] In at least one of the first polymerization step and the second polymerization step, it is preferable to use a reactive surfactant.

[0128] In the second polymerization step, the method of adding the monomer component (M2) to the product obtained in the first polymerization step, specifically the method of adding a mixture of an oil phase containing the monomer component (M2) and an aqueous phase containing a surfactant to the product obtained in the first polymerization step, is not particularly limited. The entire amount of the monomer component (M2) may be added at once before carrying out the polymerization reaction, or the monomer component (M2) may be added little by little while carrying out the polymerization reaction.

[0129] The polymerization temperature in the second polymerization step can be any suitable polymerization temperature, as long as it is suitable for emulsion polymerization and does not impair the effects of the present invention. Such polymerization temperatures are preferably 30°C to 120°C, more preferably 50°C to 100°C. For example, the polymerization temperature in the second polymerization step may be set to 30°C to 90°C as the initial polymerization temperature, and then increased to 70°C to 120°C as the later polymerization temperature.

[0130] The polymerization time in the second polymerization step can be any appropriate polymerization time, as long as it is suitable for emulsion polymerization and does not impair the effects of the present invention. Such polymerization time is preferably 1 to 48 hours, and more preferably 1 to 24 hours, at the initial polymerization temperature.

[0131] <Other steps> The above two-step polymerization process yields a slurry, which is a dispersion containing particles. After the second polymerization step, the particles may be washed, classified, dried, etc., as needed.

[0132] <Dispersion> The resin particles according to the embodiments of the present invention may be used as a dispersion as needed. Such a dispersion includes the resin particles according to the embodiments of the present invention and a dispersion medium, wherein the resin particles according to the embodiments of the present invention are dispersed in the dispersion medium as a dispersed phase. The dispersion may be used as is, in the form of a slurry obtained after the polymerization step in the above manufacturing method, or it may be used as a solvent dispersion or resin dispersion substituted with another dispersion medium, for example.

[0133] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0134] <Average Particle Diameter> The Z-average particle diameter of the resin particles was measured using dynamic light scattering, and the measured Z-average particle diameter was taken as the average particle diameter of the obtained resin particles. Specifically, first, the obtained slurry-like resin particles were diluted with deionized water, and a laser beam was irradiated onto the aqueous dispersion adjusted to 0.1% by weight, and the scattered light intensity scattered from the resin particles was measured over time in microseconds. Then, the Z-average particle diameter of the resin particles was determined by fitting the detected scattering intensity distribution due to the resin particles to a normal distribution and calculating the average particle diameter using the cumulant analysis method. This measurement of the Z-average particle diameter can be easily performed using a commercially available particle diameter analyzer. In the following examples and comparative examples, the Z-average particle diameter was measured using a particle diameter analyzer (Malvern Zetasizer Nano ZS). Typically, commercially available particle diameter analyzers are equipped with data analysis software, which automatically analyzes the measurement data to calculate the Z-average particle diameter.

[0135] <Dielectric Properties of Resin Particles> The dielectric properties of the resin particles were measured using a dielectric constant measuring device (ADMS01Nc series) manufactured by AET Corporation. The measurements were performed at a frequency of 10 GHz, in a measurement environment of 23°C, and with a relative humidity of 51 ± 1%. The dielectric loss tangent of the resin particles was calculated based on perturbation theory using a resonator.

[0136] <Glass Transition Temperature of Resin Particles> The glass transition temperature (Tg) of resin particles was measured using the method described in JIS K7121:1987, 2012 "Method for Measuring Transition Temperature of Plastics". However, the temperature conditions were as follows: A differential scanning calorimeter DSC7000X, AS-3 (manufactured by Hitachi Science Co., Ltd.) was used. Approximately 6 mg of the sample was packed into the bottom of an aluminum measuring container without any gaps. Using alumina as the reference material under a nitrogen gas flow rate of 20 ml / min, the temperature was raised from -80°C to 200°C at a heating rate of 20°C / min and held for 10 minutes. After the heat treatment, the temperature was raised to 200°C at a heating rate of 20°C / min under a nitrogen gas flow rate of 20 ml / min, and the intermediate glass transition temperature was calculated from the DSC curve obtained. The intermediate glass transition temperature was determined according to the standard (9.3 "Method for determining the glass transition temperature"). If multiple glass transition temperatures were in the range of -40.0°C to -20.0°C, the intermediate glass transition temperature determined from the largest endothermic shift in the DSC curve within the range of -40.0°C to -20.0°C was defined as the first glass transition temperature (Tg1). If multiple glass transition temperatures were in the range of 100.0°C to 140.0°C, the intermediate glass transition temperature determined from the largest endothermic shift in the DSC curve within the range of 100.0°C to 140.0°C was defined as the second glass transition temperature (Tg2).

[0137] <Ingredients Used> The ingredients used are as follows:

[0138] [Aromatic monofunctional monomers] ・Styrene

[0139] [Aromatic crosslinkable monomers] ・Divinylbenzene (DVB) 810 (manufactured by Nippon Steel Chemical & Material Co., Ltd., containing 81% by weight of divinylbenzene, 19% by weight of ethyl vinylbenzene)

[0140] [Acrylic monofunctional monomers] Methyl methacrylate, glycidyl methacrylate, 2-methacryloyloxyethyl succinate (light ester HO-MS(N), manufactured by Kyoeisha Chemical Co., Ltd.)

[0141] [Acrylic crosslinkable monomers] ・Ethylene glycol dimethacrylate

[0142] [Reactive softening components] ・Partially hydrogenated polybutadiene (hydrogenation rate 85%) (manufactured by Nippon Soda Co., Ltd., product name "BI-3015") ・Partially hydrogenated polybutadiene (hydrogenation rate 60%) (manufactured by Nippon Soda Co., Ltd., product name "BI-3040")

[0143] [Polymerization initiators] ・Lauroyl peroxide (manufactured by NOF Corporation, trade name "Perloyl L") ・4,4'-Azobis(4-cyanovaleric acid)

[0144] [Aqueous media] ・Ion-exchanged water

[0145] [Surfactants] ・Bis(polyoxyethylene phenyl ether) methacrylate sulfate ammonium salt (manufactured by Nippon Emulsifier Co., Ltd., product name "Antox MS-60") ・Polyoxyethylene styrene-propenylphenyl ether (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name "Aqualon AN-5065") ・Polyoxyethylene styrene-propenylphenyl ether sulfate ammonium salt (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name "Aqualon AR-3025") ・Polyoxyethylene styrene-propenylphenyl ether sulfate ammonium salt (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name "Aqualon AR-10")

[0146] [Example 1] Oil phase 1, oil phase 2, aqueous phase 1, and aqueous phase 2 were prepared with the compositions shown in Table 1.

[0147] Oil phase 1 and aqueous phase 1 were mixed and dispersed for 5 minutes at a rotation speed of 7,000 rpm using a Polytron homogenizer "PT10-35" (manufactured by Central Science Trading Co., Ltd.). Then, the mixture was emulsified at a processing pressure of 20 MPa using a high-pressure emulsifier NVL-AS200 (manufactured by Yoshida Machinery Industry Co., Ltd.) to prepare a suspension. Polymerization was carried out by heating the obtained suspension at 70°C for 3 hours (first polymerization step).

[0148] In a separate container, oil phase 2 and aqueous phase 2 were mixed and dispersed for 5 minutes at a rotation speed of 7,000 rpm using a Polytron homogenizer "PT10-35" (manufactured by Central Science Trading Co., Ltd.) to obtain a monomer mixture. The monomer mixture was added to the reactor after the first polymerization step was completed. At this time, the entire amount of monomer mixture was added at once. After the addition was complete, polymerization was carried out at 70°C for 2 hours, and then the temperature was raised to 90°C and polymerization was carried out for another 2 hours (second polymerization step).

[0149] After the polymerization reaction was complete, the resulting dispersion was cooled and then classified by passing it through a 500-mesh (24 μm mesh) screen to obtain a dispersion containing the resin particles of Example 1. The obtained dispersion was heated and dried to obtain resin particles (1) as a dried powder. The results of various measurements are shown in Table 1.

[0150] [Examples 2-3] Resin particles (2) to (3) of Examples 2-3 were obtained in the same manner as in Example 1, except that the composition of oil phase 2 and aqueous phase 2 were changed as shown in Table 1. The results of various measurements are shown in Table 1.

[0151] [Example 4] Oil phase 1, oil phase 2, aqueous phase 1, and aqueous phase 2 were prepared with the compositions shown in Table 1.

[0152] Oil phase 1 and aqueous phase 1 were mixed and dispersed for 5 minutes at a rotation speed of 7,000 rpm using a Polytron homogenizer "PT10-35" (manufactured by Central Science Trading Co., Ltd.). Then, the mixture was emulsified at a processing pressure of 20 MPa using a high-pressure emulsifier NVL-AS200 (manufactured by Yoshida Machinery Industry Co., Ltd.) to prepare a suspension. Polymerization was carried out by heating the obtained suspension at 70°C for 3 hours (first polymerization step).

[0153] In a separate container, oil phase 2 and aqueous phase 2 were mixed and dispersed for 5 minutes at a rotation speed of 7,000 rpm using a Polytron homogenizer "PT10-35" (manufactured by Central Science Trading Co., Ltd.) to obtain a monomer mixture. The monomer mixture was added to the reactor, which had completed the first polymerization step, over a period of 2 hours. During this time, the reactor temperature was maintained at 70°C. After the addition was complete, polymerization was carried out at 70°C for 2 hours, and then the temperature was raised to 90°C for another 2 hours of polymerization (second polymerization step).

[0154] After the polymerization reaction was complete, the resulting dispersion was cooled and then classified by passing it through a 500-mesh (24 μm mesh) screen to obtain a dispersion containing the resin particles of Example 4. The obtained dispersion was heated and dried to obtain resin particles (4) as a dried powder. The results of various measurements are shown in Table 1.

[0155] [Examples 5 and 6] Resin particles (5) and resin particles (6) of Examples 5 and 6 were obtained in the same manner as in Example 1, except that the composition of the oil phase 2 and the water phase 2 were changed as shown in Table 1. The results of various measurements are shown in Table 1.

[0156] [Example 7] Resin particles (7) of Example 7 were obtained in the same manner as in Example 1, except that the composition of oil phase 1 was changed as shown in Table 1. Various measurement results are shown in Table 1.

[0157] [Example 8] Resin particles (8) of Example 8 were obtained in the same manner as in Example 1, except that the composition of aqueous phase 1 was changed as shown in Table 1. The results of various measurements are shown in Table 1.

[0158] [Comparative Example 1] Oil phase 1 and aqueous phase 1 prepared with the compositions shown in Table 1 were mixed and dispersed for 5 minutes at a rotation speed of 7,000 rpm using a Polytron homogenizer "PT10-35" (manufactured by Central Science Trading Co., Ltd.). Then, the mixture was emulsified at a processing pressure of 20 MPa using a high-pressure emulsifier NVL-AS200 (manufactured by Yoshida Machinery Industry Co., Ltd.) to prepare a suspension. The obtained suspension was polymerized at 70°C for 3 hours, and then the temperature was raised to 90°C for another 2 hours.

[0159] After the polymerization reaction was complete, the resulting dispersion was cooled and then classified by passing it through a 500-mesh (24 μm mesh) screen to obtain a dispersion containing the resin particles of Comparative Example 1. The obtained dispersion was heated and dried to obtain resin particles (C1) as a dried powder. The results of various measurements are shown in Table 1.

[0160]

[0161] <Performance Evaluation: Stress Relaxation Evaluation of Particle-Added Films> 0.425 g of particles obtained in Example 1 and Comparative Example 1, 8.3 g of ethyl acetate, and 1.7 g of solvent-soluble polyimide KPI-MX300F (manufactured by Kawamura Sangyo Co., Ltd.) were defoamed and stirred using a planetary stirring defoamer (KURABO Co., Ltd., "Mazelstar KK-250") to prepare an evaluation mixture. The evaluation mixture was coated onto a 5 mm thick glass plate using an applicator set to a wet thickness of 250 μm. The ethyl acetate was removed by heating at 60°C for 30 minutes, 90°C for 10 minutes, 150°C for 30 minutes, and 200°C for 30 minutes, and then cooled to room temperature to obtain a film containing particles. Films were also prepared in the same manner as above, with 0.425 g of silica filler with an average particle size of 0.5 μm added instead of the resin particles obtained in Example 1 and Comparative Example 1. Furthermore, a film without particles was prepared in the same manner, except that no particles were added. The obtained film was cut into 10 mm wide x 80 mm long pieces to serve as test specimens. Tensile stress relaxation tests were performed on each test specimen using a Shimadzu Corporation "Autograph AG-X plus 100kN" universal testing machine and a Shimadzu Corporation "TRAPEZIUM-X" universal testing machine data processing machine. The test specimens were conditioned for 16 hours under a standard atmosphere of JIS K 7100:1999 symbol "23 / 50" and class 2 before being used for measurement. Measurements were performed under the same environment, specifically according to the following conditions: Chuck spacing: 60 mm, test speed: 0.5 mm / min. After deflection correction, the test was started. After the start of the test, when the strain of the test specimen reached 1.0%, the movement of the grips was stopped and the specimen was held in that position for 5 minutes. The strain of the test specimen was measured by the amount of crosshead movement. In the above test, the tensile stress σ0 of the specimen was measured when the strain of the specimen reached 1.0%, and the tensile stress σ5 of the specimen was measured after holding it for 5 minutes after stopping the movement of the gripping device. The stress relaxation rate R was calculated using the following formula: R (%) = 100 × (σ0 - σ5) / σ0. Five tests were performed, and the arithmetic mean of the five measurement results is shown in Table 2.

[0162]

[0163] <Performance Evaluation: Bending Test of Particle-Added Epoxy Resin> An evaluation epoxy resin composition was prepared by defoaming and stirring 1.2 g of particles obtained in the Examples and Comparative Examples, 12 g of bisphenol A type liquid epoxy resin (product name "EPICLON840", manufactured by DIC Corporation), and 0.6 g of imidazole-based epoxy resin curing agent (product name "2E4MZ", manufactured by Shikoku Chemicals, Inc.) using a planetary stirring defoamer (manufactured by KURABO Corporation, "Mazelstar KK-250"). The resin particles obtained in the Examples were those from Examples 1 and 5, and the resin particles obtained in the Comparative Examples were those from Comparative Example 1. In addition, an evaluation epoxy resin composition was prepared in the same manner as above, in which silica filler with an average particle diameter of 0.5 μm or 1.2 g of silicone particles with an average particle diameter of 5 μm was added instead of the resin particles obtained in the Examples and Comparative Examples. Furthermore, an evaluation epoxy resin composition without particles was prepared in the same manner, except that particles were not added. Test specimens were prepared by placing the evaluation epoxy resin composition into a silicone mold pre-formed to the specimen shape (length 65 mm, width 10 mm, thickness 3 mm), and curing the epoxy resin composition by heating it in the following order: 50°C for 17 hours, 80°C for 1 hour, and 100°C for 1 hour. Three test specimens were prepared. The test specimens were conditioned for 16 hours under a standard atmosphere of JIS K7100:1999 symbol "23 / 50" and grade 2 before being used for measurement. The fracture energy of the test specimens was measured by bending test in accordance with JIS K7171:2008. The bending test was performed using a Shimadzu "Autograph AG-X plus 100kN" universal testing machine and a Shimadzu "TRAPEZIUM-X" universal testing machine data processing machine. Measurements were performed under the same environment, and the test speed was 2 mm / min. The radius of the pressurized wedge and the tip of the pivot point was set to 5R, and the distance between the pivot points was set to 48 mm.

[0164] The measurement results are shown in Table 3. Table 3 shows the relative values, with the fracture energy of the test specimen of the particle-free epoxy resin composition set to 100.

[0165]

[0166] Resin particles according to embodiments of the present invention can be used in semiconductor components and the like.

Claims

1. Resin particles having a first glass transition temperature and a second glass transition temperature, wherein the first glass transition temperature is -40.0°C to -20.0°C, the second glass transition temperature is 100.0°C to 140.0°C, and the dielectric loss tangent at a measurement frequency of 10 GHz is 0.0050 or less.

2. Resin particles according to claim 1, wherein the average particle diameter is 0.1 μm to 10.0 μm.

3. Resin particles according to claim 1, comprising a polymer P obtained by the reaction of a composition C containing a monomer component (M), wherein the monomer component (M) comprises a crosslinkable monomer (a) and a monofunctional monomer (b).

4. The resin particles according to claim 3, wherein composition C comprises a reactive soft component that is reactive with the monomer component (M).

5. The resin particles according to claim 4, wherein the crosslinkable monomer (a) includes an aromatic crosslinkable monomer, and when the total of the monomer component (M) and the reactive soft component is 100 parts by weight, the aromatic crosslinkable monomer is greater than 0 parts by weight and 30 parts by weight or less.

6. The resin particles according to claim 4, wherein the monofunctional monomer (b) includes an aromatic monofunctional monomer, and when the total amount of the monomer component (M) and the reactive soft component is 100 parts by weight, the aromatic monofunctional monomer is 20 parts by weight or more.

7. The resin particles according to claim 4, wherein the reactive soft component comprises polybutadiene.

8. The resin particles according to claim 4, wherein when the total amount of the monomer component (M) and the reactive soft component is 100 parts by weight, the reactive soft component is greater than 0 parts by weight and 30 parts by weight or less.

9. The resin particles according to claim 4, wherein when the total amount of the monomer component (M) and the reactive soft component is 100 parts by weight, the (meth)acrylic compound is less than 20 parts by weight.

10. The resin particles according to claim 1, wherein the dielectric loss tangent at a measurement frequency of 10 GHz is 0.0030 or less.

11. Resin particles according to claim 1, for use in a resin composition for semiconductor components.

12. A resin composition for semiconductor components containing the resin particles described in claim 11.

13. A dispersion containing the resin particles described in claim 1.

14. A method for producing resin particles, comprising a two-stage polymerization process consisting of a first polymerization step and a second polymerization step, wherein in the first polymerization step, a composition C1 containing a first monomer component (M1) and a reactive soft component is subjected to a suspension polymerization reaction, and in the second polymerization step, the product obtained in the first polymerization step and a second monomer component (M2) are subjected to an emulsion polymerization reaction, wherein the first monomer component (M1) contains a crosslinkable monomer (a1) and a monofunctional monomer (b1), and the second monomer component (M2) contains a crosslinkable monomer (a2) and a monofunctional monomer (b2).

15. The method for producing resin particles according to claim 14, wherein the crosslinkable monomer (a1) comprises an aromatic crosslinkable monomer, and the monofunctional monomer (b1) comprises an aromatic monofunctional monomer.

16. The method for producing resin particles according to claim 14, wherein the reactive soft component contains polybutadiene.

Images